Thyrotropin and free thyroxine levels and coronary artery disease: cross-sectional analysis of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil)

Data on the association between subclinical thyroid dysfunction and coronary artery disease (CAD) is scarce. We aimed to analyze the association between thyroid function and CAD using baseline data from the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil). We included subjects with normal thyroid function (0.4-4.0 mIU/L, and normal free thyroxine, FT4, or 0.8 to 1.9 ng/dL), subclinical hypothyroidism (SCHypo; TSH>4.0 mIU/L and normal FT4), and subclinical hyperthyroidism (SCHyper; TSH<0.4 mIU/L and normal FT4) evaluated by coronary computed tomography angiography. We excluded individuals using medications that interfere in thyroid function or with past medical history of cardiovascular disease. Logistic regression models evaluated the presence of CAD, segment involvement score (SIS) >4, and segment severity score (SSS) >4 of coronary arteries as the dependent variables, and quintiles of TSH and FT4 as the independent variables, adjusted for demographical data and cardiovascular risk factors. We included 767 subjects, median age 58 years (IQR=55-63), 378 (49.3%) women, 697 euthyroid (90.9%), 57 (7.4%) with SCHypo, and 13 (1.7%) with SCHyper. No association between TSH and FT4 quintiles and CAD prevalence was noted. Similarly, no association between TSH levels and the extent or severity of CAD, represented by SIS>4 and SSS>4 were seen. Restricting analysis to euthyroid subjects did not alter the results. TSH levels were not significantly associated with the presence, extent, or severity of CAD in a middle-aged healthy population.

亚临床甲状腺功能异常与冠状动脉疾病（coronary artery disease, CAD）的关联相关研究数据较为匮乏。本研究旨在借助巴西成人健康纵向研究（Brazilian Longitudinal Study of Adult Health, ELSA-Brasil）的基线数据，分析甲状腺功能与冠状动脉疾病之间的关联。本研究纳入的受试者包括：甲状腺功能正常者（促甲状腺激素0.4~4.0 mIU/L，游离甲状腺素（free thyroxine, FT4）正常，即0.8~1.9 ng/dL）、亚临床甲状腺功能减退症（subclinical hypothyroidism, SCHypo；促甲状腺激素>4.0 mIU/L且游离甲状腺素正常）以及亚临床甲状腺功能亢进症（subclinical hyperthyroidism, SCHyper；促甲状腺激素<0.4 mIU/L且游离甲状腺素正常），所有受试者均接受了冠状动脉计算机断层血管造影评估。本研究排除了服用干扰甲状腺功能药物，或既往有心血管疾病病史的受试者。本研究采用logistic回归模型，以冠状动脉疾病患病情况、冠状动脉节段受累评分（segment involvement score, SIS）>4以及冠状动脉节段严重程度评分（segment severity score, SSS）>4作为因变量，以促甲状腺激素（thyroid-stimulating hormone, TSH）和游离甲状腺素的五分位数作为自变量，并校正了人口学资料与心血管危险因素。本研究共纳入767名受试者，年龄中位数为58岁（四分位间距IQR=55~63），其中女性378名（占比49.3%）；甲状腺功能正常者697名（占比90.9%），亚临床甲状腺功能减退症患者57名（占比7.4%），亚临床甲状腺功能亢进症患者13名（占比1.7%）。未观察到促甲状腺激素与游离甲状腺素的五分位数与冠状动脉疾病患病率之间存在关联。同样，未发现促甲状腺激素水平与以节段受累评分>4、节段严重程度评分>4所代表的冠状动脉疾病范围及严重程度之间存在关联。将分析范围限定于甲状腺功能正常受试者时，研究结果并未发生改变。在中年健康人群中，促甲状腺激素水平与冠状动脉疾病的患病情况、病变范围及严重程度均无显著关联。